Study of polyacrylamide/Cr (III) hydrogels for conformance control in injection wells to enhance chemical flooding process

This study is to increase the efficiency of chemical injection by reducing the injectivity in high permeability zone, especially fractures or super-K zones, which are inevitably encountered in carbonate reservoirs. A chemical gelant system in liquid composed of polymer and crosslinker will be introduced in injection wells and form semi-solid gels in the formation. This technique will divert the successively injected fluids (chemical solution) into unswept formation and ensure the success of a chemical EOR process. A polyacrylamide/Cr (III) gel system was studied in terms of sol/gel diagram, kinetics of the gelation, viscoelastic properties of gels with the help of oscillatory shear rheometer, and long-term stabilities with a measure of syneresis. The lab results present excellent performance at the conditions of a carbonate reservoir. A core flooding test was conducted to identify plugging capacity with disproportionate permeability reduction to brine and to oil. Results confirmed a successful application of gelant system as conformance control agent for a carbonate reservoir.